1. Field of the Invention
The present invention relates to an apparatus and method of performing an error recovery process in an asymmetric clustering file system, and more particularly, to an apparatus and method of distributively processing the recovery of a data error due to failure of a data server in an asymmetric clustering file system.
2. Description of the Related Art
In general, an asymmetric clustering file system includes a metadata server managing metadata of a file, a plurality of data servers managing data of a file, and a plurality of clients storing or searching a file.
The metadata server, the plurality of data servers, and the plurality of clients are connected to and communicate with one another over a local network.
The plurality of data servers provide a single mass storage space using a virtualization technology. The storage space may be freely managed by adding and deleting the data servers or volumes included in the data servers.
Such a system managing a plurality of data servers considers a failure rate that is proportional to the number of servers managed by the system. Accordingly, a system managing a plurality of data servers utilizes a method of providing parity for recovery while distributing data, such as RAID (Redundant Array of Inexpensive Disks) level-5, or a mirroring technology that preliminarily provides a copy of data. The mirroring technology suffers from a low efficiency due to duplicated storage. Accordingly, a data distributive storage structure using parity is preferred in the case of requiring fault tolerance.
The data distributive storage structure using parity may recover data stored in a storage device having a single error among data storage devices by using parity. The data is recovered by performing an error correction scheme (for example, exclusive-OR) on the other data constituting parity and the parity. For this purpose, the single data recovery process should be accompanied with a reading process on a number of data and parity.
In most of the known technologies, a metadata server having detected an error in a storage device recovers data stored in the storage device.